A severe thunderstorm warning is being issued for parts of the Bay of Plenty.

The areas include, South Waikato, Whakatāne, Rotorua and Wairoa.

"At 03:22 pm, MetService weather radar detected severe thunderstorms near Waikite Valley, Gurthrie, Waiotapu, Reporoa, Rerewhakaaitu, Murupara, Te Whaiti, and the Ikawhenua Range.

"These severe thunderstorms are moving towards the eastsoutheast, and are expected to lie near Reporoa, Rerewhakaaitu, Murupara, Galatea, Te Whaiti, and the Ikawhenua Range at 3.52pm, and near Murupara, Galatea, Kopuriki, the Ikawhenua Range, and Ruatahuna at 4.22pm," says a MetService spokesperson.

These thunderstorms are expected to be accompanied by torrential rain.

"Torrential rain can cause surface and/or flash flooding about streams, gullies and urban areas, and make driving conditions extremely hazardous."

The National Emergency Management Agency advises that as storms approach you should:

• Take shelter, preferably indoors away from windows;
• Avoid sheltering under trees, if outside;
• Get back to land, if outdoors on the water;
• Move cars under cover or away from trees;
• Secure any loose objects around your property;
• Check that drains and gutters are clear;
• Be ready to slow down or stop, if driving.
• During and after the storm, you should also:
• Beware of fallen trees and power lines;
• Avoid streams and drains as you may be swept away in flash flooding.